Server Core is a minimal server installation option for computers running on the operating system. Server Core provides a low-maintenance server environment with limited functionality.
Before with Windows Server 2008 R2 and Windows Server 2008, there was no way to convert to a full installation or a Server Core installation without completely reinstalling the operating system.
In Windows Server 2012, an administrator now has the ability to convert between a Server Core installation and a full installation (Server with a GUI) as needed.
If you are using server with a GUI you can use the server manager, “Remove Roles and Features Wizard” to switch to Server Core Installation.
In Windows Server 2012, a large investment in Server Core capabilities was made to increase deployment flexibility and also bring Server Core support to more server roles. The following roles are supported in Server Core installation:
- Active Directory Certificate Services
- Active Directory Domain Services
- DHCP Server
- DNS Server
- File Services (including File Server Resource Manager)
- Active Directory Lightweight Directory Services (AD LDS)
- Print and Document Services
- Streaming Media Services
- Web Server (including a subset of ASP.NET)
- Windows Server Update Server
- Active Directory Rights Management Server
- Routing and Remote Access Server and the following sub-roles:
- Remote Desktop Services Connection Broker
Benefit of Server Core
Reduced Servicing: Because Server Core installs only what is required for a manageable DHCP, File, DNS, Media Services, and Active Directory server, less servicing is required.
Reduced Management: Because less is installed on a Server Core-based server, less management is required.
Reduced attack surface: Because there is less running on the server, there is less attack surface.
Server Core limitations
There is no Windows shell and very limited GUI functionality.
There is limited MSI support (unattended mode only).
When you install Windows Server 2012, Server Core installation is the default. However you can choose between Server Core Installation and Server with a GUI.
Because you can freely switch between these options at any time later, one approach might be to initially install the Server with a GUI option, use the graphical tools to configure the server, and then later switch to the Server Core Installation option.
An intermediate state is possible where you start with a Server with a GUI installation and then remove Server Graphical Shell, resulting in a server that comprises the “Minimal Server Interface,” Microsoft Management Console (MMC), Server Manager, and a subset of Control Panel.
A server in Minimal Server Interface mode is about 300 MB smaller than the same server in Server with a GUI mode. A server in Server Core mode is about 4 GB smaller than the same server in Server with a GUI mode.
Additionally, you can install the Desktop Experience feature which enables you to install a variety of Windows 8 features on your server running Windows Server 2012. If you use Windows Server 2012 as your primary operating system, you might want to have some of these Windows 8 features available for your daily use.
If you are using Server Core Installation to swith to Server with a GUI do:
If you are using Server with a GUI you can switch to Server Core Installation using the Remove Roles and Features Wizard
or with the following PowerShell cmdlet:
Uninstall-WindowsFeature Server-Gui-Mgmt-Infra, Server-Gui-Shell